The present invention relates to optical devices, and specifically to light intensifying devices adapted to be coupled to a scope.
Light intensifying devices, commonly referred to as night vision equipment, have existed for many years. Typically, these devices have an objective lens through which light is received, a light intensifying module which amplifies the received light, and an eyepiece through which the amplified image is viewed.
Some optical devices have been combined with light intensifying modules to enable the optical device to be utilized in low light conditions. U.S. Pat. No. 4,822,994 discloses a fire arm scope which is adapted to be utilized with a light intensifying device. Here, the scope during normal daylight use has a first section with an objective lens and a second section with an eyepiece. The two sections are coupled together with the use of a flange. In low light conditions, the two sections are separated and an image intensifying module is coupled between the two sections. This procedure however is complex and time consuming. Moreover, the first and second sections and the light intensifying module are all designed to be compatible for use only with each other.
Optical devices have also been designed with interchangeable eyepieces. These devices typically include an eyepiece adapted for use in daylight which may be removed and replaced with a nighttime eyepiece including a light intensifying module. The conversion of the device from daylight to nighttime use is time consuming because the daytime eyepiece must be removed and stowed prior to the mounting of the nighttime eyepiece. The same problem also presents itself when the optical device is converted from nighttime use to daytime use. Furthermore, the light intensifier must be used in conjunction with the other components and may not be utilized alone as a light intensifying device.
Another problem associated with multiple component or interchangeable component devices has been the corruption of sealed components. Optical devices typically include sealed chambers between the objective lens and the eyepiece. These chambers are filled with a gas to prevent moisture from condensing upon the lens of the device. However, should the components be separated these internal components become exposed to ambient conditions wherein moisture may enter the device and thereby cause problems with the reliability and operation of the device.
Light intensifying devices have also been designed to be mounted to existing optical devices. These light intensifying devices typically include mechanical clamping systems which encompass the eyepiece of the optical device. These clamping devices however often provide an uneven force upon the eyepiece which causes damage. Furthermore, these clamping devices are typically split rings the ends of which are brought together in clamping the device to the eyepiece. These split ring clamping devices do not provide an air tight seal between the light intensifying device and the optical device, the lack of which allows moisture to enter the space between these devices even when they are mounted together.
Accordingly, it is seen that a need remains a device that is easily and quickly coupled to an existing optical instrument to convert it to nighttime use without compromising the integrity of the optical instrument. It is to the provision of such therefore that the present invention is primarily directed.
In a preferred form of the invention, an image intensifying device is disclosed which is adapted to be mounted to a scope having an objective lens and an eyepiece of a select outside diameter. The image intensifying device comprises an image intensifying module, an eyepiece coupled to the image intensifying module which includes an eyepiece lens, and an objective lens unit coupled to the image intensifying module opposite the image intensifying device eyepiece. The objective lens unit has an objective lens and a housing containing the objective lens. The housing has a tubular, elastic collar having a distal end with an inside diameter less than the outside diameter of the scope eyepiece. With this construction, the image intensifying device is mounted to the scope by stretching the elastic collar distal end about the scope eyepiece with the objective lens unit substantially aligned with the scope eyepiece.